The present disclosure relates to an image reading device which is used in a digital copying machine, an image scanner or the like and which scans an original document so as to read it, and to an image forming apparatus which includes such an image reading device.
Conventionally, as an image reading device incorporated in a multifunctional machine using an electrophotographic process or the like, there is an image reading device that includes an original document transport device (Automatic Document Feeder) which sequentially feeds a sheet-shaped original document to an original document placement stage (contact glass) in order to read the original document and which ejects it from the top of the original document placement stage after the completion of the reading. In the image reading device as described above, two types of reading methods can be adopted that are: a sheet-through method in which in a state where a reading module is fixed to an image reading position, the original document is automatically transported by the original document transport device and is read; and an original document fixing method in which each time the original document is read, an original document holder is opened and closed, in which the reading module is moved so as to perform scanning while the original document on the original document placement stage is replaced on an individual sheet basis and in which the original document placed on the original document placement stage is read.
In recent years, in the sheet-through method described above, a double-sided simultaneous reading method has been mainly used in which the front surface and the back surface of a double-sided original document are simultaneously read with individually different reading modules by performing an original document transport operation once with the original document transport device. The reading module for reading the back surface of the double-sided original document is arranged on the side of the original document transport device. In the original document transport device, a cover member is provided in which part of an original document transport path can be opened so that jam processing on the original document is performed.
In the image reading device, there are various types of processing which are necessary for the initial setting and the adjustment and the like of the reading module, and as one of the types of processing, light source turning-on confirmation processing is present in which the light amount data of light reflected from a white reference plate arranged opposite the reading module when a light source incorporated in the reading module is turned on is acquired and in which whether the light source is normal or abnormal is determined.
On the other hand, in the image reading device of the double-sided simultaneous reading method, a configuration is known in which with consideration given to a space within the original document transport device, convenience at the time of cleaning in a reading position and the like, the reading module for reading the back surface of the double-sided original document is arranged in the opening/closing portion of the cover member. The white reference plate is attached to the side of the cover member through the original document transport path, and when the cover member is opened, the reading module and the white reference plate are separated from each other.
In the configuration described above, in a state where the cover member is opened, even when the light source is normally turned on, the reading module cannot receive the light reflected from the white reference plate, and thus it is erroneously detected that the light source is not turned on or that an abnormally occurs in the turning on of the light source. Alternatively, even when the light source is not turned on, in the state where the cover member is opened, the reading module inevitably receives ambient light, and thus it is likely that an error cannot be detected.
An image reading device is known which determines whether or not image reading can be performed according to the result of detection of the opening and closing of an original document transport device for an image reading device and the intensity of external light detected by an external light detection means.